Researchers at Tufts University have published their research on using silk to stabilize vaccines. When preservatives like thimerosal are not used, refrigeration is the only other way to preserve vaccines from the point of manufacture to the point of vaccination. Without preservatives or refrigeration, any bacterial contaminants could pose a risk to the health of those receiving the vaccine. Moreover, all vaccines are heat-sensitive to some degree, and loss of potency is a risk when vaccines are kept outside the optimal temperature.
This new research is promising in that silk, a natural protein produced by some insects, is inert to the point that it is used to make hypoallergenic clothing and suture material to close wounds. It is also readily available. The research at Tufts is based on having the antigen — the part of the vaccine that triggers the immune response — embedded in silk produced by silkworms (the larval form of the silkmoth). The silk will then maintain the antigen regardless of the storage temperature. This way, vaccines can be stored in warm conditions without the antigen being degraded. As a result, the vaccine doesn’t lose its potency.
Should vaccine manufacturers adopt this technology, the cost associated with delivering vaccines to rural areas of the world will be lower since refrigeration will not be a concern. That could translate into cheaper vaccines for parts of the world where they are needed but are costly right now.
Tufts Now. New silk technology preserves heat-sensitive drugs for months without refrigeration. 7/9/12. http://now.tufts.edu/news-releases/new-silk-technology-preserves-heat-sensitive-
Zhang et al. Stabilization of vaccines and antibiotics in silk and preserving the cold chain. PNAS http://www.pnas.org/content/early/2012/06/29/1206210109.abstract?sid=f7e3ec14-15f7-4645-a300-accbf1488847